The present invention relates to a method and an apparatus for predicting a distillation temperature range of a hydrocarbon-containing compound.
It is generally known in petrochemical industry to perform a distillation analysis of a hydrocarbon-containing compound such as a petroleum product (e.g. gasoline and/or naphta) in order to obtain distillation data such as boiling point range and the like.
Such a distillation is usually performed according to an ASTM method, in particular the ASTM D 86 distillation method. ASTM methods are standard test methods for petroleum products, are known to those skilled in the art and will therefore not be described in detail. ASTM D 86 is a standard test method for distillation of petroleum products and covers the distillation of natural gasolines, motor gasolines, aviation gasolines, aviation turbine fuels, special boiling point spirits, naphtas, white spirit, kerosines, gas oils, distillate fuel oils, and similar petroleum products, utilizing either manual or automated equipment. ASTM stands for American Society for Testing and Materials.
Summarizing it can be said that a predetermined volume sample of a hydrocarbon-containing compound (e.g. 100 ml) is distilled under prescribed conditions. Systematic observations of thermometer readings and volumes of condensate are made and from this data, results of the test are calculated and reported.
However, in practice the well-known ASTM D 86 method is time-consuming and rather complicated and its results are subject to undesirable variations.
Therefore, there is a need to replace ASTM D 86 distilation by an analysis such as gaschromatography (GC) which offers much more compositional detail and requires less operator time per sample. However, the pure component boiling points of separated GC peaks differ in nature from D 86 boiling points and it has appeared very difficult to link GC data to distillation performance in a satisfactory manner.
Generally, a GC-analysis is performed, e.g. according to the well-known ASTM method D 2887, producing temperature/volume data, which are converted to ASTM D 86 distillation data by statistical techniques, e.g. a set of correlations.
Calculations are performed by any data processing means suitable for the purpose such as a computer.
The disadvantage of a correlation is, however,that erroneous results cannot be understood.
Further, the use of a set of correlations may show results subject to variations with the season of the year and the blending of the sample.
While the ability of GC in order to measure mixture composition is superior to other techniques, the statistical approach, however, fails to predict these variations.
Therefore, a strong need exists for a method and apparatus for predicting the distillation temperature range of a hydrocarbon-containing compound in a reliable manner without the requirement to carry out an experimental ASTM D 86 distillation method or applying correlation techniques in GC analysis.
It is now an object of the present invention to fulfil this need.
The present invention therefore provides a method for predicting a distillation temperature range of a hydrocarbon-containing compound comprising gasoline and/or naphta, said method comprising the steps of:
a) analyzing the said hydrocarbon-containing compound and determining specific physico-chemical parameters of interest;
b) processing the values of said determined parameters of interest in a predetermined mathematical distillation model;
c) calculating from said model the distillation temperature range of said hydrocarbon-containing compound; and
d) producing data representing the result of said calculating step c).
The present invention further provides an apparatus for predicting a destination temperature range of a hydrocarbon-containing compound comprising gasoline and/or naphta, said apparatus comprising a means for analyzing the said hydrocarbon-containing compound and determining specific physico-chemical parameters of interest; means for processing the values of said determined parameters of interest in a predetermined mathematical distillation model; means for calculating from said model the distillation temperature range of said hydrocarbon-containing compound; and means for producing data representing the result of the calculation.
In this manner a simple and time-saving method and apparatus have been provided to obtain petroleum product distillation parameters of interest. In particular an accurate simulation of the ASTM D 86 method can be obtained by the method and apparatus according to the present invention by processing the results from an analysis of the hydrocarbon-containing compound in a mathematical model.
In this manner, carrying out the difficult time-consuming and complicated experimental ASTM D 86 distillation method or applying unreliable sets of correlations in GC analysis is made superfluous.